Light (A, B) and scanning electron (C-I) micrographs of Plagiopyxis callida. (A, B) View of many specimens to illustrate variability in shape and size of the shell. (C, D) Apertural view showing general shape. (E) Dorsal view (F, G) Lateral view. (H) Close up view of aperture showing its oval shape and smooth apertural surface. (I) Detail of dorsal side of the shell to illustrate its smooth surface, covered with flattish particles embedded in a thick layer of organic cement.